The synthesis and hydrolysis of cholesteryl esters by acetone powder of aorta is under study. The ratio of synthesis (S) to hydrolysis (H) will be determined in aortas of rabbits and rats fed atherogenic regimens. We will also determine S/H in aortas of normal and cholesterol-fed rabbits fed a variety of currently available hypocholesteremic agents. Work on concentration and purification of enzymic activity will continue. We also plan to investigate differences in ratios of labile to stable forms of N-Acetyl-beta-D-glucosaminidase (EC 3.2.1.30) in sera of normal and hyperlipoproteinemic patients and in sera and aortas of cholesterol fed rabbits.